This invention relates generally to harvesters for collecting nuts, fruits, olives and other articles gathered directly from the ground or other prepared surface (hereafter collectively referred to as "nuts") and thereafter separating unwanted debris such as leaves, twigs, grass and dirt from the harvested nuts. More particularly, this invention is directed, but not limited, to a nut harvester which effectively and efficiently separates the nuts from the debris while reducing the airborne pollutants and emissions associated with previous nut harvesters.
The modern nut harvester performs the dual job of first collecting the windrows of nuts and intermixed debris, and then separating the nuts from the debris. The effective separation of the collected nuts from the associated debris has been the focus of many prior nut harvesting machines. One prior method to separate the intermingled nuts and debris is to pass the debris and nuts through an air stream.
Separation mechanisms which utilize an air stream passing transversely through a perforated conveyor to uplift and remove the lighter and more aerodynamically responsive trash material from the nuts are well known in the art. This conventional method often includes a centrifugal fan sufficiently powerful to create an air stream passing through a portion of a foraminous conveyor. The debris is thereby separated from the relatively heavy nuts and carried upwardly from the conveyor to be eventually discharged to the atmosphere.
In order to improve the effectiveness of the separation of the nuts from the debris, many nut harvesters include multiple or more powerful fans to thereby generate an increased airflow rate. However, the problem associated with using an air stream to separate the debris from the collected nuts are the emissions and airborne pollutants which are discharged from the nut harvester to the atmosphere. Specifically, clumps of dirt are frequently collected by the nut harvester with the nuts. The dirt clumps are broken down within the air stream and are discharged as dust thereby creating significant dust emissions during the nut harvest.
Therefore, a need exists for a nut harvester which efficiently and effectively collects the nuts from windrows on the ground and separates the collected debris from the nuts while reducing the discharge of dust emissions and airborne pollutants associated with prior nut harvesters. The need for such a nut harvester is highlighted by the existing and anticipated restrictions on dust and airborne pollution within the nut harvesting industry.